Surgical systems, in particular dental systems, comprise an instrument having a hand part, for example, a counter angle, which may be provided with a tool, for example a milling cutter—and a rotating motor that drives the tool. The hand part and the motor may be two separate pieces and interconnected by appropriate interfaces or may constitute a single piece. The instrument's controller device is often connected to the patient's chair and connected to the manual instrument by a flexible connection containing electric wires and tubes for passing air and water.
The rotary motors used in this type of hand-held instruments are more and more motors without commutators and without brushes, which have the advantage of being more robust and being capable of being sterilized completely. In order to avoid overheating of the instrument, which can be rotated at high speeds, for example up to 40,000 turns per minute or more, three-phase motors are preferable.
A rotary motor used in this type of hand-held instruments generally consists of a magnetically rotor with two poles and a stator winding with three windings. In order to set the coils on a precise angular position of the rotor for rotation which extend from 0 t/min, it is possible to equip the rotary motor with sensors, for example Hall effect sensors or magneto resistive sensors providing continuously rotor positions to the electronic control which is typically located at the exterior of the motor. Less precise solutions without sensors, are also known.
In the medical field, the allowable dimensions are very small and the bulky cables should be avoided. There is thus a need for new systems including hand tools providing mechanical and electronic miniaturization as well as an optimal reduction of the cables while preserving a maximum reliability.
The Document WO05037124, in the name of the Applicant, discloses a surgical system including a dental system, an embodiment of which is illustrated in FIG. 1. The illustrated system 1 includes a manual instrument 1 that includes a rotary motor M, two Hall effect sensors H1 and H2 arranged to determine at least one operating parameter of the motor M, and an electronic module 20.
The control device of the motor M comprises a first electronic module 10 and a flexible connection comprising the electrical conductors L1, L2, L3 and C0 for electrically connecting the first electronic module 10 with the second electronic module 20, and thus the control device to the instrument. The second electronic module 20 located inside the instrument processes output signals of the sensors H1 and H2, and transmits them to the controller device 10 through the flexible connector.
The electrical conductor L1 is the conductive phase of the motor M. From the high frequency point of view, this conductor corresponds to the neutral, for example the phase I.
The electrical conductor L2 is the conductive phase of the motor M, e.g. the phase II, on which is transmitted the drive component of the motor M, which is a low frequency signal, and the power supply high frequency component of the embedded microprocessor 26.
The electrical conductor L3 is the conductor of the phase of the motor M, for example the phase III, on which, the motor M drive component and the component of the data are transmitted, from the microprocessor 26 to the module 10.
The electrical conductor C0 is the power driver of an accessory 30, such as an incandescent lamp or LED, and the delivery driver of the information transmitted from the first electronic module 10 to the microprocessor 26. The information destined to the embedded microprocessor 26 in the instrument are encoded by frequency modulation on the electrical conductor C0.
Communications between the first electronic module 10 and the second electronic module 20, are mainly done by high frequency modulation of the conductors C0 and L3, in particular of the phase III of the motor. This has several disadvantages: it is in fact necessary to use lager volumes of magnetic elements, such as the two transformers 62 and 66 respectively associated with L3 and C0, and a demodulator 18, which rends the device expensive. The choice of the types of drivers of motor phases is accordingly limited by the fact that it should not interfere with high frequency signals. In addition, the system is sensitive to disruptions, in particular disruptions due to the existence of a common potential between four electrical conductors L1, L2, L3 and C0. Finally the system has a high cost.
Moreover, the use of the floating power supply 14 comprising an expensive PWM driver in the first electronic module 10, connected to the power supply 12 and allowing powering both the second electronic module 20, embedded in the manually actuated instrument, and the motor M trough the conductor L2, and which is potentially associated with the phase I (electrical conductor L1) of the motor M involves the use of a magnetic element, in particular the transformer 60 of lager volumes and therefore high cost.
U.S. Pat. No. 5,235,261 concerns a surgical system, in particular a dental system comprising a rotating motor for driving an instrument tool. This instrument does not have an electronic module inside the motor (second electronic module). This document does not describe an exchange of messages between a first and a second electronic module.
US2011266124 concerns a surgical system, in particular a dental system comprising an electronic circuit (second electronic module) inside the motor consisting of a fixed hardware performing predefined functions. In other words this second electronic module does not include a microprocessor. These functions are notified to the electronic management (first electronic module) of the system through six conductors. Each of these conductors carries a single signal, so that the number of signals (six) is equal to the number of conductors.
U.S. Pat. No. 5,538,423 relates to a method and a device for controlling operational parameters of a dental system, comprising an instrument having a commutator motor. This motor does not include switchable three phases, but only one variable voltage. The instrument does not have an electronic module inside the motor (second electronic module).
EP0688539 (Bien Air) concerns a dental handheld part comprising an electric driving and powering module of a lamp and an electromagnetic motor with no commutator whose connector comprises four power supply wires, i.e. three wires for the three motor coils and one wire for the lamp, the connection of the lamp taking advantage of the negative power supply line of one of the wires (or terminals). The lamp is thus connected to the power supply terminals of the motor, which can create interference problems and/or of electromagnetic compatibility (EM).
EP1753360 (Bien Air) discloses a flexible pipe connecting a dental instrument and a power supply comprising an additional power line via a dual function connector (conductive fluid and/or electricity). The additional conductor is insulated from conductors for powering a lamp and the motor and can be used to transmit a single signal.
There is therefore a need for a surgical system, especially dental system, capable of solving at least one of the disadvantages of the prior art.
There is also a need for a surgical system, especially a dental system, which is less bulky and cheaper than the known solutions.
There is also a need for a surgical system, especially a dental system, which is more reliable and does not present problems of interference and/or electromagnetic compatibility or EMC or having reduced interference problems compared to the known solutions.